Are cod and haddock set to leave the waters of Scotland's west coast?

The findings show cod and herring off Scotland’s west coast are already nearing the edge of their temperature tolerance range.

Scottish Association for Marine Science (SAMS) researchers predict cod, herring and haddock could migrate out of the west coast of Scotland ecosystem by 2100, most likely to colder waters further north.

But their research also suggests these species will gradually be replaced by more abundant communities of saithe, hake and whiting over the next few decades. From 1985 to 2013, the population of saithe and hake off the Scottish west coast has increased fourfold.

MCS Head of Fisheries and Aquaculture, Samuel Stone, says: “This research really highlights the need to closely monitor our seas and to better understand what sustainability actually looks like for our fisheries and other marine activities in the face of climate change. Rapid climate change means that it’s now more important than ever that marine management fully considers all the different uses and impacts to our shared seas.’

Lead author Dr Natalia Serpetti, a marine ecologist at SAMS, said: “These results highlight the importance of considering environmental change, as well as fishing quotas, to achieve sustainable fisheries management at an ecosystem level.

“Our results showed that warmer climate could jeopardise sustainable fishery management - rising temperature showed strong negative impact on cold water species such as grey seals, cod, haddock and herring, which all declined by 2100 under the worst-case climate warming scenario.

“Even under the best-case climate change scenario, cod and herring stocks were predicted to collapse off Scotland’s west coast.”

Researchers first tested the impact of current advised fishing quotas, along with predator/prey interactions, within the ecosystem. Cod, whiting and herring stocks - which historically show declining trends - recovered under sustainable fishery management.

The impact of rising temperatures under different climate-change scenarios were then tested while keeping fishing rates consistent with currently advised maximum sustainable yields.

These results found there would be a collapse of cold water species stocks.

Dr Serpetti’s research updated an existing marine model of the west coast of Scotland ecosystem, situated in the north-east Atlantic from the coastline to the edge of the continental shelf.

This latest method looked at how rising temperatures would affect 41 groups of species, from top predators such as whales and seals to many fish species and animals such as crabs and snails living on the sea floor.

A Scottish Government spokesman said: “We recognise that climate change is a major threat to our marine ecosystems and will continue to follow scientific advice to support a sustainable fishing industry.

“Scotland is recognised as being at the forefront of the global fight against climate change and continues to lead the UK in reducing greenhouse gas emissions.